The present disclosure generally relates to an improved counter-flow heat exchanger for a vehicle air conditioning system, and more particularly relates to an improved counter-flow heat exchanger constructed to reduce the likelihood and/or size of air bubbles developing within the heat exchanger and/or to facilitate removal of any air bubbles within the heat exchanger.
Heat exchangers for vehicle air conditioning systems typically include a pair of spaced apart tanks with a plurality of spaced apart tubes extending therebetween to fluidly connect the tanks. A heat transfer fluid, such as water or coolant, is passed through the tubes between the spaced apart tanks while an air flow is passed between the spaced apart tubes. Heat from the heat transfer fluid is imparted to the air flow passing between the spaced apart tubes, which can then be used to target select areas of the vehicle's cabin through appropriate ducting. The heat transfer fluid is delivered to the heat exchanger at a first elevated temperature through an inlet port and exits the heat exchanger at a second lower temperature through an exit port (i.e., after its heat has been imparted to the air flow passing thereby). The locations of the inlet and outlet ports are often dependent on the type of heat exchanger employed (e.g., parallel flow, counter-flow, etc.) and the orientation of the heat exchanger within a particular air conditioning system (e.g., tanks spaced horizontally apart or tanks spaced vertically apart).
One concern with heat exchangers in vehicle air conditioning systems is the elimination of any air bubbles or pockets within the heat exchanger. Such air bubbles or pockets can have a deleterious effect of the heating efficiency of the heat exchanger. Another concern relates to layout considerations of the vehicle, which can impact the size of the heat exchanger, the orientation of the heat exchanger and/or the location of the inlet and outlet ports of the heat exchanger. Oftentimes, the air bubble or pocket concern competes with the layout considerations in a given vehicle design. For example, designing the heat exchanger of a particular size, orienting the heat exchanger in a particular position and/or requiring the inlet and outlet ports to face a certain direction can result in a heat exchanger that is prone to developing and capturing air bubbles or pockets. Conversely, designing an efficient heat exchanger that has few problems with air bubbles or pockets can result in a heat exchanger that severely limits layout options within the air conditioning system and/or the vehicle generally.